Relay unit and electrical junction box

ABSTRACT

A relay unit and an electrical junction box are disclosed as including a plurality of relays ( 2 A˜ 2 D) and a power supply bus bar ( 3 ) for supplying electric power to the plurality of relays ( 2 A˜ 2 D) which are contained in an electrical junction box, wherein electric power is supplied to the respective relays ( 2 A˜ 2 D) from the power supply bus bar ( 3 ) via relevant fuses ( 16   a   ˜16   d ).

BACKGROUND OF THE INVENTION

The present invention relates to a relay unit having a plurality of relays, and a relay to be applied to such a relay unit, and an electrical junction box in which such a relay unit is mounted.

A relay box, which serves as an electrical junction box which an attempt has heretofore been made to be improved, is disclosed in FIG. 1.

In FIG. 1, the relay box 120 is comprised of a relay cavity 121, a fuse cavity 122, a FL cavity 123 and a bus bar 124, with respective cavities 121, 122, 123 receiving electronic component parts such as a relay, a fuse and a FL. The bus bar 124 provides an electrical connection for the respective cavities 121, 122, 123. Further, the respective cavities 121, 122, 123 are inserted with pressure connection terminals, each coupled to an electric wiring through a pressure connection, through which desired electric signals are inputted or outputted. With such a structure, the relay box 120 is formed with a desired relay circuit.

However, in the relay box 120, since the relays and the fuses are positioned at separate locations, respectively, the relay box 120 has been inevitably increased in size.

SUMMARY OF THE INVENTION

The present invention has been made with a view to addressing the above issues and has an object to provide a relay unit and an electrical junction box which has a fuse and which is compact in structure.

According to a first aspect of the present invention, there is provided a relay unit comprising: a plurality of relays; and a power supply bus bar supplying power supply current to said plurality of relays; wherein said power supply bus bar allows power supply current to be supplied to said plurality of relays via respective fuses.

With such a structure, it is possible to provide the relay unit in which the plurality of fuses are contained in close proximity to the plurality of relays. Further, since electric power current is applied to the respective fuses by means of the power supply bus bar, there is no need for discrete electrical wirings for electrical connection, with a resultant improved workability in assembly of the relay unit.

According to a second aspect of the present invention, there is provided an electrical junction box comprising: a plurality of relays; and a power supply bus bar supplying power supply current to said plurality of relays; wherein said power supply bus bar allows power supply current to be supplied to said plurality of relays via respective fuses.

With such a structure, since the plurality of relays and the power supply bus bar are contained together within the electrical junction box to allow power supply current to pass through the respective fuses to the plurality of relays, the electrical junction box is formed in a compact and simple structure while an assembling workability is highly improved.

Other aspect and advantages of the invention will become more apparent from the following description, taken in conjunction with the accompanying drawings, illustrating by way of example the principles of the invention.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a plan view of a relay box which an attempt has been made to be improved by inventors of the present patent application;

FIG. 2 is a structural view illustrating basic bus bar circuit components and a power supply bus bar component of a relay unit of a first preferred embodiment according to the present invention wherein;

FIG. 3 is a circuit diagram of the relay unit shown in FIG. 1 under a condition prior to trimming operation of trimmer joint portions intervened between the basic bus bar circuit components;

FIG. 4 is a view illustrating circuit diagrams of object circuitries Nos. 1 to 4 which are formed by trimming the trimmer joint portions of the basic bus bar circuit components and associated bus bar trimming and conducting patterns;

FIG. 5 is a view illustrating circuit diagrams of object circuitries Nos. 5 and 6 which are formed by trimming the trimmer joint portions of the basic bus bar circuit components and associated bus bar trimming and conducting patterns;

FIG. 6 is a view illustrating circuit diagrams of object circuitries Nos. 7 and 8 which are formed by trimming the trimmer joint portions of the basic bus bar circuit components and associated bus bar trimming and conducting patterns;

FIG. 7 is a view illustrating a circuit diagram of an object circuitry No. 9 which is formed by trimming the trimmer joint portions of the basic bus bar circuit components and associated bus bar trimming and conducting patterns;

FIG. 8 is a circuit diagram illustrating a detailed example of a practical mounting circuit forming the relay unit of the first preferred embodiment according to the present invention;

FIG. 9 is a structural view illustrating trimmed conditions and associated circuit patterns which form the practical mounting circuit of the relay unit of the first preferred embodiment according to the present invention;

FIG. 10 is a cross sectional view (which involves a front view of a relay according to the present invention) of an electrical junction box of a second preferred embodiment according to the present invention;

FIG. 11 is a plan view of the electrical junction box shown in FIG. 10;

FIG. 12 is an enlarged view illustrating connector portions between the relays and the relevant fuses shown in FIG. 10; and

FIG. 13 is a cross sectional view of an electrical junction box of a third preferred embodiment according to the present invention.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

To describe the present invention more in detail, a relay unit of a first preferred embodiment of the present invention will be explained below with reference to FIGS. 2 to 9, wherein FIG. 2 is a structural view illustrating a basic bus bar circuit body 4 and a power supply bus bar 3 which form a relay unit 1 of the first preferred embodiment, FIG. 3 is a circuit diagram of the relay unit 1 with a plurality of electrically conductive trimmer joint portions 9 a to 9 j, formed in the basic bus bar circuit body 4, shown in a state prior to trimming operation.

As shown in FIGS. 2 and 3, the relay unit 1 is comprised of four sets of laterally arrayed relays 2A to 2D which is located in a unit case (not shown) in close proximity relationship to one another in the same horizontal plane, and the power supply bus bar 3 located in an area adjacent to the laterally arrayed relays 2A to 2D. The four sets of relays 2A to 2D include four relay switch element elements SW (see FIG. 3), relay coil elements L (see FIG. 3) associated with respective relay switches SW, and the basic bus bar circuit body 4.

The basic bus bar circuit body 4 is composed of laterally spaced, switch connector bus bars 5 a to 5 d and laterally spaced, switch connector bus bars 6 a to 6 d placed in close proximity to the switch connector bus bars 5 a to 5 d, respectively, to be correlated therewith for forming respective pairs of switch connector circuit components each for the relay switch element SW, and laterally spaced, coil connector bus bars 7 a to 7 d and laterally spaced, coil connector bus bars 8 a to 8 d placed in close proximity to the switch connector bus bars 7 a to 7 d, respectively, to be correlated therewith for forming respective pairs of coil connector circuit components each for the coil element L, with four pairs of switch connector circuit components being located in parallel to one another which the four pairs of coil connector circuit components are enclosed in the associated switch connector circuit components. The basic bus bar circuit body 4 is further composed of the electrically conductive trimmer joint portions 9 a to 9 j which are integrally and preliminarily formed at suitable positions between the respective switch connector bus bars 5 a to 5 d, and 6 a to 6 d and the respective coil connector bus bars 7 a to 7 d and 8 a to 8 d. Thus, the basic bus bar circuit body 4 is made of an electrically conductive material formed with a bus bar forming die of a single piece, with each of the respective joint portions 9 a to 9 j being formed in a narrow width to provide an ease of cutting operation to thereby provide a trimming function.

In particular, the joint portions 9 a to 9 j are intervened between one of the switch connector bus bars 5 a to 5 d and the other one of the coil connector bus bars 7 a to 7 d within the same one of the relays 2A to 2D and intervened between each of the switch connector bus bar pairs 5 a to 5 d and 6 a to 6 d and the other one of the switch connector bus bars 5 a to 5 d. Suitably cutting a suitable part of the plurality of electrically conductive trimmer joint portions 9 a to 9 j allows a variety of selected relay circuit patterns to be readily formed as will be described below in detail. In FIG. 3, to provide a clarification, the basic bus bar circuit body 4 is formed with the joint portions, bearing the same reference numerals as those used in FIG. 2, which can be cut out for the trimming function by the cutting step.

The switch connector bus bars 5 a to 5 d, of one part of the relays 2A to 2D, have upper ends integrally formed with downstream fuse joint portions 11 a to 11 d, respectively, to be connected with respective fuses, and lower ends integrally formed with connector joint relay terminals 12 a, 12 e, 12 i and 12 m, respectively, to be connected with respective connectors. The downstream fuse joint portions 11 a to 11 d protrude in respective fuse mounting areas (not shown) of the unit case (not shown), and the relay terminals 12 a, 12 e, 12 i and 12 m protrude into respective connector hood areas (not shown) of the unit case (not shown). That is, the downstream fuse joint portions 11 a to 11 d and the relay terminals 12 a, 12 e, 12 i and 12 m protrude in directions opposed to one another.

The switch connector bus bars 6 a to 6 d and both the coil connector bus bars 7 a to 7 d and 8 a of the other part of the relays 2A to 2D, have lower ends integrally formed with connector joint relay terminals 112 b to 12 d, 12 f to 12 h, 12 j to 12 l and 12 n to 12 p, respectively, to be connected with relevant connectors. The respective relay terminals 12 b to 12 d, 12 f to 12 h, 12 j to 12 l and 12 n to 12 p protrude into the respective connector hood areas (not shown) of the unit case (not shown) in the same manner as the switch connector bus bars 12 a, 12 e, 12 j ad 12 m of the aforementioned one part of the relays. That is, all the relay terminals 12 a to 12 p are formed in parallel to one another in the lower connector hood area (not shown) in which the relevant connectors are mounted to provide electrical connections between the relay terminals and outside associated component parts.

The power supply bus bar 3 is constructed of a laterally extending main bar 3 a in the close proximity to upper distal edges of downstream fuse joint portions 11 a to 11 d of the relays 2A to 2D, four upstream fuse joint portions 13 a to 13 d which project upward from the main bar 3 a, and a power supply terminal 14 bent downward from a left distal end of the main bar 3 a. The main bar 3 a is located on an inner surface in the unit case (not shown), with the four upstream fuse joint portions 13 a to 13 d being located in four fuse mounting areas (not shown) in the unit case (not shown), respectively. The four upstream fuse joint portions 13 a to 13 d are aligned on respective positions opposed to the downstream fuse joint portions 11 a to 11 d, respectively, with the upstream fuse joint portions 13 a to 13 d and the downstream fuse joint portions 11 a to 11 d forming the sum of four sets of fuse joint section pairs 15 a to 15 d. In addition, the respective upstream fuse joint portions 13 a to 13 d and the respective downstream fuse joint portions 11 a to 11 d are formed with cutout portions which extend from respective upper edges in a downward direction. Inserting fuses 16 a to 16 d into the respective cutout portions of the fuse joint section pairs 15 a to 15 d allows them to be fixedly mounted therein.

The power supply terminal 14 is formed such that it protrudes into a power supply hood area (not shown) of the unit case (not shown) and is electrically connected to an associated external component part via a connector (not shown) mounted in a connector hood area (not shown). Thus, the relay unit 1 has the structure to allow electric power to be supplied from the power supply bus 3 to the four relays 2A to 2D via the respective fuses 16 a to 16 d.

Now, a detailed description will be given to show how an object circuitry is constructed by suitably cutting or trimming suitable parts of the plurality of trimmer joint portions 9 a to 9 j. FIG. 4 is a view illustrating a circuit diagram for object circuitries No. 1 to No. 4 and associated bus bar trimming and conducting patterns formed in the basic bus bar circuit body 4. FIG. 5 a view illustrating a circuit diagram for object circuitries No. 5 and No. 6 and associated bus bar trimming and conducting patterns formed in the basic bus bar circuit body 4. FIG. 6 is a view illustrating a circuit diagram for object circuitries No. 7 and No. 8 and associated bus bar trimming and conducting patterns formed in the basic bus bar circuit body 4. FIG. 7 a view illustrating a circuit diagram for an object circuitry No. 9 and an associated bus bar trimming and conducting pattern formed in the basic bus bar circuit body 4. In FIGS. 4 to 7, trimmer areas of the trimmer joint potions 9 a to 9 j to be cut out are shown with black areas and non-trimmer areas of the trimmer joint portions 9 a to 9 j are indicated with hatched areas.

The object circuitry No. 1 is a through-circuit which is electrically conductive at all times to pass electric power current through the fuse 16 a. For example, when using the relay 2A, electric power is supplied from the power supply bus bar 3 and is outputted from the relay terminal 12 a. In this case, a desired object circuitry is formed by cutting out (trimming) all the trimmer joint portions 9 a to 9 c related with the relay 2A.

The object circuitry No. 2 is a relay circuit wherein power supply current is not supplied through the fuse 16 a and which is turned on or turned off in response to a high or low level of a control signal (not shown). For example, when using the relay 2A, electric power is supplied from the relay terminal 12 a, and a pair of the relay terminals 12 b, 12 c serve as a control terminal to output electric power from the relay terminal 12 d. In this case, also, a desired object circuitry is formed by cutting out (trimming) all the trimmer joint portions 9 a to 9 c related with the relay 2A.

The object circuitry No. 3 is a relay circuit wherein power supply current is supplied through the fuse 16 a and which is turned on or turned off in response to the high or low level of the control signal (not shown). For example, when using the relay 2A, electric power is supplied from the power supply bus bar 3, and a pair of the relay terminals 12 b, 12 c serve as the control terminals, respectively, to output electric power from the relay terminal 12 d. In this case, also, a desired object circuitry is formed by cutting out (trimming) all the trimmer joint portions 9 a to 9 c related with the relay 2A.

The object circuitry No. 4 is a relay circuit wherein power supply current is supplied through the fuse 16 a to the two relay terminals 12 c, 12 d which are electrically conductive at all times. For example, when using the relay 2A, electric power is supplied from the power supply bus bar 3, allowing power supply current to be outputted through the pair of the relay terminals 12 c, 12 d. In this case, also, a desired object circuitry is formed by cutting out (trimming) the trimmer joint portions 9 b, 9 c without cutting out the trimmer joint portion 9 a among the trimmer joint portions 9 a to 9 c related with the relay 2A.

The object circuitry No. 5 is a power supply circuit wherein power supply current is supplied through the fuse 16 a to the four relay terminals 12 c, 12 d, 12 g, 12 h which are rendered electrically conductive at all times. For example, when using the relays 2A, 2B, electric power is supplied from the power supply bus bar 3 and is outputted through the four relay terminals 12 c, 12 d, 12 g, 12 h. In this case, a desired object circuitry is formed by cutting out (trimming) the trimmer joint portions 9 c, 9 e, 9 f without cutting out the remaining trimmer joint portions 9 a, 9 b, 9 d among the trimmer joint portions 9 a to 9 f related with the relays 2A, 2B.

The object circuitry No. 6 is a relay circuit wherein power supply current is supplied through the fuse 16 a and is branched into the two relays 2A, 2B through which branched electric current flows are supplied in response to the high and low level of the respective control signals to be applied to the relays 2A, 2B. For example, when using the relays 2A, 2B, electric power is supplied from the power supply bus bar 3, allowing power supply current to be outputted through the relay terminals 12 d, 12 h with the actions of the respective control terminals formed with the two pairs of the relay terminals 12 b, 12 c, 12 f, 12 g. In this case, a desired object circuitry is formed by cutting out (trimming) the trimmer joint portions 9 a, 9 c to 9 f without cutting out the trimmer joint portion 9 b among the trimmer joint portions 9 a to 9 f related with the relays 2A, 2B.

The object circuitry No. 7 is a relay circuit wherein power supply current is supplied through the fuse 16 a and is branched into the two branched power supply current flows which are controlled in response to the high and low level of a single control signal. For example, when using the relay 2A, electric power is supplied from the power supply bus bar 3, and the pair of the relay terminals 12 b, 12 c serve as the control terminals, respectively, to output electric power from the relay terminals 12 a, 12 d. In this case, a desired object circuitry is formed by cutting out (trimming) all the trimmer joint portions 9 a to 9 c related with the relay 2A.

The object circuitry No. 8 is a relay circuit wherein power supply current is branched through the fuse 16 c into three branched current flows which are controlled in response to the high and low level of the single control signal. For example, when using the relays 2C, 2D, electric power is supplied from the power supply bus bar 3, allowing power supply current to be outputted through the three relay terminals 12 l, 12 o, 12 p with the actions of the respective control terminals formed with the pair of the relay terminals 12 j, 12 k. In this case, a desired object circuitry is formed by cutting out (trimming) the trimmer joint portions 9 e to 9 g without cutting out the trimmer joint portions 9 i, 9 j among the trimmer joint portions 9 e to 9 j related with the relays 2C, 2D.

The object circuitry No. 9 is a relay circuit wherein power supply current is not supplied through the fuses 16 a to 16 d and the two relay terminals 12 c, 12 d are electrically conductive at all times. For example, when using the relay 2A, electric power is supplied from the relay terminal 12 a, allowing power supply current to be outputted through the pair of the relay terminals 12 c, 12 d. In this case, a desired object circuitry is formed by cutting out (trimming) the trimmer joint portions 9 b, 9 c without cutting out the trimmer joint portion 9 a among the trimmer joint portions 9 a to 9 c related with the relay 2A.

It will now be appreciated from the foregoing description that a desired mounting circuit can be formed in an arbitrary combination of either one of or more than two object circuitries discussed above. A detailed example of a practical mounting circuit will be described below in conjunction with FIGS. 8 and 9, with FIG. 8 showing a circuit diagram while FIG. 9 showing a particular basic bus bar circuit body 4 formed in a particularly trimmed condition in a desired conductive pattern to form the practical mounting circuit.

As viewed in FIG. 8, the mounting circuit is composed of the object circuitries Nos. 3, 2 and 8, which are employed in a combined state. In the object circuitry No. 3, the relay 2A is employed under a condition where the three trimmer joint portions 9 a, 9 b, 9 c are cut out. Then, electric power is supplied from the power supply bus bar 3 via the fuse 16 a, with the pair of the relay terminals 12 b, 12 c serving as the control terminals, respectively, whereas the relay terminal 12 d serves as the output terminal. In the object circuitry No. 2, the relay 2B is employed under a condition where the three trimmer joint portions 9 d, 9 e, 9 f are cut out. Then, electric power is supplied from the relay terminal 12 e, and the pair of the relay terminals 12 f, 12 g serve as the control terminals, respectively, whereas the relay terminal 12 h serves as the output terminal. In the object circuitry No. 8, the relays 2C, 2D are employed under a condition where the two trimmer joint portions 9 g, 9 h are cut out. Then, electric power is supplied from the power supply bus bar 3 via the fuse 16 c, and the pair of the relay terminals 12 j, 12 k serving as the control terminals, respectively, whereas the relay terminals12 l, 12 o, 12 p serve as the output terminals, respectively.

From the foregoing description given above, in the first preferred embodiment, the presence of the unit case (not shown) containing the plurality of relays 2A to 2D which incorporate the power supply bus bras 3, respectively, through which electric power is supplied to the respective relays 2A to 2D via the respective fuses 16 a to 16 d enables the relay unit 1 containing the plurality of fuses 16 a to 16 d in the vicinities of the plurality of relays 2A to 2D, respectively, to be constructed in a compact structure. In addition, since electric power is supplied to the respective fuses 16 a to 16 d via the power supply bus bar 3, there is no need for providing electrical connection using discrete electric wirings, with a resultant improvement in workability in an assembly of the relay unit.

In the first preferred embodiment, further, the presence of the switch connector bus bars 5 a to 5 d, in one part, integrally formed with the downstream fuse joint portions 11 a to 11 d and the relay terminals 12 a, 12 e, 12 i, 12 m, respectively, enables the relay terminals 12 a, 12 e, 12 i, 12 m to be used for supplying electric power to the associated relays 2A to 2D without passing power supply current through the relevant fuses 16 a to 16 d. As such, in the absence of the relevant fuses 16 a to 16 d which are mounted, it is possible to use the relays 2A to 2D as independent components or through-circuits as viewed in the object circuitries Nos. 2 and 9.

In the first preferred embodiment, further, the presence of the switch connector bus bars 5 a to 5 d, in one part, integrally formed with the downstream fuse joint portions 11 a to 11 d and the relay terminals 12 a, 12 e, 12 i, 12 m, respectively, both of which extend in opposed relationship allows the downstream fuse joint portions 11 a to 11 d and the relay terminals 12 a, 12 e, 12 j, 12 m to be located in dispersed areas within the unit case. Accordingly, the fuse mounting areas and the connector mounting areas are separately located in different minimum areas, resulting in the relay unit 1 formed in a simplified structure with a compact configuration. In the first preferred embodiment, also, although the downward fuse joint portions 11 a to 11 d protrude upward and the relay terminals 12 a, 12 e, 12 i, 12 m protrude downward from respective body sections of the switch connector bus bars 5 a to 5 d, it is suffice for the downward fuse joint portions and the relay terminals not to be formed in the same orientation, and a modification may be made such that the downward fuse joint portions 11 a to 11 d protrude upward while the relay terminals 12 a, 12 e, 12 i, 12 m protrude in a lateral direction, is desired.

In the aforementioned first preferred embodiment, further, the presence of the plurality of pairs of fuse joint portions 15 a to 15 d formed with the downstream fuse joint portions 11 a to 11 d, integrally formed with the respective switch connector bus bars 5 a to 5 d of the plurality of relays, and the upstream fuse joint portions 13 a to 13 d, integrally formed with the power supply bus bar 3, which are located in opposed relationship to one another, enables the fuse joint portions 15 a to 15 d to be constructed in a simplified structure with a minimum number of component parts. Thus, the relay unit may be simplified in structure to have a compact configuration.

In the relay unit 1 of the first preferred embodiment, also, it is possible for various relay circuit patterns to be formed merely by trimming selected ones of the plurality of trimmer joint portions 9 a to 9 j along desired trimming patterns. This results in an easy to comply with variations in desired relay circuit patterns for the mounting circuits with a mere trimming operation at suitable trimming points among the trimmer joint portions 9 a to 9 j. When it is desired to interconnect the switch connector bars 5 a to 5 d, 6 a to 6 d, 7 a to 7 d and 8 a to 8 d to one another, the trimmer joint portions 9 a to 9 j, which are joined to the switch joint bus bars 5 a to 5 d, 6 a to 6 d, 7 a to 7 d and 8 a to 8 d, remain untrimmed. As a consequence, it is easy to perform a joint absorption among the switch connector bus bars 5 d, 6 a to 6 d, 7 a to 7 d and 8 a to 8 d and also a joint absorption of wire harnesses (not shown).

In the first preferred embodiment discussed above, further, the presence of the plurality of trimmer joint portions 9 a to 9 j are preliminarily intervened between the switch connector bus bars 5 a to 5 d and the relevant coil connector bus bars 7 a to 7 d within the respective relays 2A to 2D and, within the different relays 2A to 2D, the plurality of trimmer joint portions 9 a to 9 j are intervened between the pairs of the switch connector bus bars 5 a to 5 d and 6 a to 6 d and the switch connector bus bars 5 a to 5 d allows the trimmer joint portions 9 a, 9 d, 9 g, 9 j formed in the relays 2A to 2D within the relay unit 1 to be selectively trimmed. As such, a plurality of pairs of coil connector terminals 12 b, 12 c, 12 f, 12 g, 12 j, 12 k, 12 n, 12 o can be used as respective control terminal pairs and used as through-circuits without trimming the aforementioned trimmer joint portions 9 a, 9 d, 9 g, 9 j. Further, selectively trimming the trimmer joint portions 9 b, 9 c, 9 e, 9 f, 9 h, 9 i intervening between the different relays 2A to 2D allows the neighboring relays 2A to 2D to be formed into independent circuitries which are separate from one another and, without trimming the aforementioned trimmer joint portions 9 b, 9 c, 9 e, 9 f, 9 h, 9 i, the neighboring relays 2A to 2D may be utilized as mixed circuitries. Consequently, it is possible for a variety of circuitries in various circuit patterns to be obtained in an easy fashion in a low manufacturing cost.

In the aforementioned first preferred embodiment, further, since the switch connector circuit components and the coil connector circuit components are composed of the switch connector bus bars 5 a to 5 d and 6 a to 6 d and the coil connector bus bars 7 a to 7 d and 8 a to 8 d, a single bus bar forming die may be prepared for complying with the various circuit patterns of the mounting circuit, with a resultant contribution in a reduction of the manufacturing cost of the bus bar forming die. Also, since the respective circuit bodies have increased strengths, the respective circuit bodies may be integrally formed with the respective terminals.

In the first preferred embodiment, further, since the respective switch connector bus bars 5 a to 5 d and 6 a to 6 d and the coil connector bus bars 7 a to 7 d and 8 a to 8 d are formed with the respective relay terminals 12 a to 12 p to be connected to the respective connectors, there is no need for additionally preparing the relay terminals separate from the relays 2A to 2D, the relay unit may be simplified in structure to have a compact configuration.

In the first preferred embodiment, also, although the relay unit 1 has been shown and described as being composed of the four sets of the relays 2A to 2D, the relay unit 1 may include two, three, or more than five relays. In the aforementioned preferred embodiment, further, since the relay unit 1 includes the four sets of the relays 2A to 2D and the nine patterns, the relay unit 1 may have the mounting circuitries in the number of circuit patterns corresponding to the fourth power of nine.

FIGS. 10 to 12 show a relay unit and an electrical junction box of a second preferred embodiment according to the present invention. FIG. 10 is a cross sectional view (involving a front view of the relay according to the present invention) of the electrical junction box according to the present invention. FIG. 11 is a plan view of the electrical junction box shown in FIG. 10, and FIG. 12 is an enlarged view illustrating the relays and the fuses shown in FIG. 10. In the description, the words “upward” or “downward” are used on the basis of a reference in conjunction with the structure shown in FIG. 10.

In FIGS. 10 to 12, the electrical junction box to be mounted to a vehicle such as an automobile includes a box body 21 (which corresponds to the unit case described with reference to the first preferred embodiment) which is comprised of a main cover 22 made of plastic resin, an undercover 23 made of plastic resin, the plurality of fuses 24 arrayed in a row in parallel relationship with respect to one another and accommodated in the main cover 22, the plurality of fuses 25 arrayed in a row in parallel relationship with respect to one another and accommodated in the undercover 23, and the pair of power supply bus bars 26.

Further, the box body 21 is formed with an electric power supply section 27 to which electric power is supplied from an electric power supply such as a battery (not shown), and a plurality of connector joint portions 28 which are connected to the associated relays and the associated fuses 24.

The main cover 22 is formed with an upper wall 30 and a rear wall 31 which form a hood portion 29 of the electric power supply section 27, a plurality of fuse cavities 32 associated with the respective fuses 24, and a plurality of lock portions 33 which engages the undercover 23.

The upper wall 30 formed on the main cover 22 has a flat shape having a distal end whose inner surface is formed with a lock segment 35 to clamp a connector 34 for supplying electric power to the power supply section 27. Also, the upper wall 30 and the rear wall 31 are formed in a shape so as to intersect with one another at an inner base portion of the upper wall 30.

The respective fuse cavities 32 have desired profiles to allow the associated fuses 24 to be inserted from the respective distal portions in a downward direction. Further, each of the fuse cavities 32 is formed with a terminal receiver compartment 36. In addition, each cavity 32 is formed so as to penetrate in upper and lower directions. In the illustrated embodiment, each fuse cavity has the same shape as that of the related art structure.

In FIG. 10, further, the fuse cavities 32, located at first, third and fifth locations counting from the right side, refer to other fuse cavities which are defined in appended claims. These fuse cavities are located to effectively use spaces in a row in which the relays 25 are arrayed and between the neighboring fuses 24 to which the associated relays 25 are connected.

The lock portions 33 are integrally formed with a fuse cavity forming wall 37, on which the fuse cavities 32 are formed, and extend downward from a peripheral edge thereof.

The undercover 23 is formed with a hood body 38 and a rear wall 39 which form the hood portion 29, a plurality of relay compartments 40 for accommodating the relays 25, respectively, a plurality of through-holes 41 formed between the adjacent relay compartments 40, a plurality of hood compartments 42 which form the connector joint portions 28, respectively, and a plurality of lock segments 43 formed in respective projections which engage the lock portions 33 of the main cover 22.

The hood body 38 is formed in the undercover 23 in a C-shape in cross section (as viewed from a connecting direction of the connector 34). Also, the hood body 38 is formed in a structure to clamp the upper wall 30 of the main cover 22 through some suitable means.

On the other hand, the rear wall 39, which is formed at a bottom area of the hood 38, is formed to allow the aforementioned power supply bus bar 26 to be sandwiched between the rear wall 31 of the main cover 22 and the rear wall 39 to retain the same in a fixed place. Further, the rear wall 39 forms a part of the relay compartment 40, which is closest to the electric power supply section 27, and also serves as a resting member to support a substrate 54 which will be discussed later.

The relay compartment 40 is shaped to have a profile to comply with an external shape of the relay 25 for fully accommodating the relay 25. Also, the relay compartment 40 has a bottom wall formed with a plurality of terminal insertion slots 44 which communicate with an inner side of the relay compartment 40. Also, the through-hole 41 communicates with an inner side of the hood portion 42 in the same manner as the terminal insertion slots 44.

Although each fuse 24 is of the same structure as the related art practice and a detailed description of the same is herein omitted, each fuse 24 is constructed of a tab-shaped upstream terminal 45, a tab-shaped downstream terminal 46, and a soluble body (not shown) intervening between the upstream and downstream terminals.

The plurality of relays 25 are arrayed in five sets. Thus, like in the first preferred embodiment, the relay unit is comprised of five sets of relay switch elements (not shown), relay coil elements (not shown) and basic bus bar circuit components (not shown). Since the basic bus bar circuit components have the same structures as those of the first preferred embodiment except for the number of sets of the circuit components, a detailed description of the same is herein omitted. Further, the relay 25 is constructed of a circuit substrate (not shown) which is made of plastic resin, an outer cover 47 formed in a box shape and enclosing the circuit substrate, a relay coil (not shown) internally located in the outer cover 47, a one terminal 48 which extends upward from an upper wall of the outer cover 47, and three other terminals (with only two terminals being shown) 49 which extend from the aforementioned circuit substrate via the terminal insertion slots 44. In the illustrated preferred embodiment, further, the one terminal 48 extends straightly upward, whereas the other terminals (which correspond to the relay terminals 12 a to 12 p of the first preferred embodiment) 49 extend straightly downward.

The one terminal 48 is formed at its one end with a fuse connector portion 50 shaped in a bifurcated profile to be connected to the downstream terminal 46 of the fuse 24. Further, the other end of the one terminal 48 is formed with a contact which is located inside the outer cover 47.

On the other hand, all of the three terminals 49 are formed in tab-shapes and form the connector joint portions 28, respectively.

It is to be noted that the one terminal 48 may not extend through the upper wall of the outer cover 47 but through a side wall thereof. In such a case, although the relays 24 are arrayed in a right and left direction of the relays 25 such that the relay unit may encounter a difficulty in obtaining the same miniaturization result as that obtained in the box body 21 of the presently filed preferred embodiment, it is possible to obtain an improved workability in a reliable manner as will be described later.

The aforementioned power supply bus bar 26 is comprised of a tab 51 which forms a part of the power supply section 27, a first intermediate component 52 which is sandwiched between the rear wall 31 of the main cover 22 and the rear wall 39 of the undercover 23, and a second intermediate component 53 located in a plane parallel to the aforementioned upper walls of the relays 25. Further, second intermediate component 53 of the power supply bus bar 26 is placed on the circuit substrate made of plastic resin and fixed thereto.

The tab 51 of the power supply bus bar 26 is located so as to protrude inside the hood body 38 to allow electric power to be supplied through the tab 51. Further, the second intermediate component 53 of the power supply bus bar 26 is formed with a plurality of upwardly extending fuse connector portions 55 to which the upstream terminals 45 of the fuses 24 are connected, respectively. Each connector portion 55 is formed in the same shape as the fuse connector portion 50 formed in the one terminal 48 (with the fuse connector portions 55 being located in a rear side of the fuse connector portion 50 in FIGS. 12 and 14 and bearing the respective reference numerals enclosed in parentheses).

Located on respective distal ends of the rear wall 39 and the relay compartments 40 is the circuit substrate 54, to which the aforementioned power supply bus bar 26 and the plurality of bus bars 56, which is different from the power supply bus bar 26, are fixedly connected. Further, the circuit substrate 54 is formed with a plurality of through-bores 57 through which the associated terminals 48 of the respective relays 25 extend, and a plurality of through-holes 58 located for the bus bars 56. The through-holes 58 are formed in alignment with the through-holes 41 of the undercover 23.

One end of each bus bar 56, which is placed on the circuit substrate 54 and fixed thereto independently of the power supply bus bar 26, is formed with a plurality of fuse connector portions 59 to be connected to the downstream terminals 46 of the associated fuses 24 to be inserted through the first, third and fifth fuse cavities 32counting from the right side in FIG. 12. Also, the other end of each bus bar 56 is formed with an elongated tab 60 which extends through the through-hole 58 of the circuit substrate 54 and the through-hole 41 of the undercover 23 and which forms a part of each connector portion 28 together with the other terminals 49 of the relay 25.

Now, a detailed description will be given below on how the box body 21 of the electrical junction box of the present invention is assembled.

Initially, a first step is carried out for placing and receiving the relays 25 in the respective relay compartments 40 of the undercover 23. In particular, each relay 25 is inserted into the relevant relay compartment 40 from the side of the other terminals 49. Then, upon fully receipt of the relay 25, the other terminals 49 of the relay 25 protrude into the relevant hood portion 42 via the associated terminal insertion slots 44. Also, only the one terminal 48 of the relay 25 extends upward from the relay compartment 40.

Under such a condition, a second step is carried out for locating the circuit substrate 54, on which the power supply bus bars 26 and 56 are placed and fixed thereto, on the upper distal ends of the respective relay compartments 40. In particular, the circuit substrate 54 is placed on the upper distal ends of the relay compartment 40 while allowing the one terminal 48 of the relay 25 to be inserted through the relevant through-hole 57 while, at the same time, allowing the tab 60 of the bus bar 56 to be inserted through the relevant through-hole 41 of the undercover 23. Then, the circuit substrate 54 is fully placed over the upper distal ends of the respective relay compartments 40 and, when the tab 60 of the bas bar 56 protrudes inside the hood portion 42, the connector joint portion 28 is formed.

In a consecutive operation, a third step is carried out for permitting the main cover 22 to be mated with the undercover 23. When the lock portions 33 of the main cover 22 engage the lock segments 43 of the undercover 23, the power supply bus bar 26 and the associated circuit substrate 54 are held in a sandwiched state between the main cover 22 and the undercover 23 and retained in a fixed place. Also, in this instance, terminal receiver compartment 36 of each fuse cavity 32 receives therein the fuse connector portion 50 of the one terminal 48 of the relay 25, the fuse connector portion 55 of the power supply bus bar 26, the fuse connector portion 59 of the bus bar 56 and the fuse connector portion 55 of the power supply bus bar 26.

Then, lastly, under a circumstance described above, the fuses 24 are inserted into the relevant fuse cavities 32 such that the upstream terminal 45 and the downstream terminal 46 are connected to the relevant fuse connector portion 50 of the one terminal 48 of the relay 25, the fuse connector portion 55 of the power supply bus bar 26, the fuse connector portion 59 of the bus bar 56 and the fuse connector portion 55 of the power supply bus bar 26, thereby completing a series of assembling steps.

As will be appreciated from the foregoing description, in the second preferred embodiment, the presence of the box body (which corresponds to the unit case described with reference to the first preferred embodiment) containing the plurality of relays 25 and the power supply bus bar 26 for supplying power supply current to these relays 25 allows the relay unit, in which the plurality of fuses are contained in the vicinity of the plurality of relays in a single box body, to be provided. This results in the relay unit, which incorporates the fuses 24, and accordingly the electrical junction box to be manufactured in compact structures. Also, since power supply current is applied to the respective fuses 24 via the power supply bus bar 26, there is no need for discrete electric wirings to be connected, thereby highly improving workability in assembly.

According to the relay 25 of the second preferred embodiment, further, since the one terminal 48 and the other terminals 49 are formed at locations different from one another while the one terminal 48 is formed with the fuse connector portion 50, it is possible for the downstream terminal 46 of each fuse 24 to be directly connected to the connector portion 50. Accordingly, there is no need for providing discrete electrical wirings that would be required between the relays 25 and the fuses 24 in the related art structure, providing an ease of laminating the fuses 24 in the upper side of the relays 25 for thereby improving an assembling workability.

According to the electrical junction box of the present invention, also, the presence of the relay 25 having the aforementioned advantages enables the electrical junction box to be formed such that the downstream terminals 46 of the fuses 24 can be directly coupled to the fuse connector portions 50 of the relays 25. That is, inserting the fuses 24 into the fuse cavities 32, under a condition wherein the relays 25 are received in the relay compartments 40, allows the electrical junction box to be constructed such that the one terminal 48, which is inserted into the relevant fuse cavity 32, of each relay 25 is brought into direct electrical contact with the downstream terminal 46 of the relevant fuse 24. Consequently, the relays 25 and the fuses 24 can be connected to one another without the need for the discrete electrical wirings, resulting in an improved workability.

According to the electrical junction box of the present invention, the presence of the relay 25 having the advantages described above enables the fuses 24 to be received in the stacked state with the relevant relays 25 within the electrical junction box. Thus, such an arrangement allows the electrical junction box to be miniaturized.

According to the electrical junction box, further, the presence of the connector joint portions 28 allows the electrical junction box to be constructed such that a package of the wire harnesses can be connected to the other terminals 49 of each relay 25 through a connector joint. Therefore, there is no need for troublesome load works for individually locating separate terminals with electrical wirings onto relevant positions corresponding to the other terminals 49 of the relay 25 one by one, with a resultant improved assembling workability.

According to the electrical junction box of the present invention, furthermore, the presence of the power supply bus bar 26 enables electrical connection between the upstream terminal 45 of the fuse 24 and the power supply section 27. As a consequent, there is no need for connecting the above component parts together with electric wires one by one, resulting in an improved workability.

FIG. 13 is a cross sectional view illustrating an electrical junction box of a third preferred embodiment according to the present invention, with like parts bearing the same reference numerals as those used in the aforementioned illustrated embodiments for omitting a redundant description of the same component parts. In the fourth preferred embodiment, the electrical junction box is constructed of a box body 61 and a lower cover 62, with the box body 61 being formed with connector joint portions 63 whose bottom walls are spaced from a bottom wall 64 of the lower cover 62 by a given distance. Also, it is to be noted that the box body 61 and the lower cover 62 are fixedly secured to one another with suitable fixtures.

More particularly, the box body 61 is constructed of a main cover 65, the aforementioned fuses 24, the aforementioned relays 25 and the aforementioned power supply bus bar 26. Further, the main cover 65 is formed with a hood section 66, relay compartments 67 and fuse cavities 68 in a sequence from the bottom wall 64 of the lower cover 62. Each of the relay compartments 67 is formed with a slit 69 with which a lock 70 of the relay 25 is brought into engagement when the relay 25 is received in the relay compartment 67 to preclude the relay 25 from being dislocated.

Also, the aforementioned fuses 24, the aforementioned relays 25 and the aforementioned power supply bus bar 26 are electrically connected to one another in the same manner as those of the preferred embodiments described above. Therefore, a detailed description of the same is herein omitted.

With the structure described above, when the relay 25 is received in the relay compartment 67, the other terminals 49 protrude into the hood section 66 to form the connector joint portion 63. Then, the connector 71 is connected to the connector joint portion 63 through the connector coupling.

Since the connector joint portion 63 is spaced from the bottom wall 64 of the lower cover 62 by the given distance, a sufficient space is enhanced for achieving the connector coupling of the connector 71 of a wire harness 72 while providing an improved receiving capacity for the wire harness 72, etc. Thus, it is possible for the workability to be highly improved, with the other aforementioned advantages being also obtained in the presently filed preferred embodiment.

Also, with a specific arrangement wherein the connector 71 is fixed to the bottom wall 64 of the lower cover 62, the connector joint portion 63 may be readily coupled to the connector 71 during an assembly, with a resultant improved workability.

From the foregoing description given above, it is to be noted that various other modifications may be made without departing the spirit of the present invention. For example, without forming the fuse connector portion 50 at the one terminal 48 which in turn remains in the tab shape, it is possible for the downstream terminal 46 of the fuse 24 to be electrically connected by means of a male-female type junction terminal of a structure in the related art. In such a case, the relay of the present invention may be featured as follows:

(1) The relay is featured in that the one terminal, which corresponds to the downstream terminal of the fuse, is arranged to be located in a different position so as to extend in an orientation different from that in which the other terminals extend.

(2) In the relay (1) defined above, the one terminal is formed with a fuse connector portion which enables the aforementioned downstream terminal of the aforementioned fuse to be directly connected to the aforementioned one terminal.

It will now be appreciated from the foregoing description that in accordance with the present invention, the presence of the plurality of relays and the power supply bus bar contained in a particular area in close proximity to one another to apply electric power supply to the respective relays via the relevant fuses allows the relay unit, which is enabled to also contain the associated fuses in the vicinity of the relevant relays, to be provided. This results in the relay unit which is simple and compact in structure even contained with the relevant fuses. Further, the presence of the power supply bus bar contained in the relay unit for supplying power supply current to various component parts via the respective fuses eliminates the need for discrete electric wirings while highly increasing workability in an assembly of the relay unit.

Another important advantage of the present invention concerns the electrical junction box containing the plurality of relays and the power supply bus bar through which power supply current is supplied to the respective relays via the relevant fuses for thereby providing a compact and simplified structure at a low manufacturing cost while eliminating the need for preparing discrete electric wirings specifically designed for the particular electrical junction box.

While specific embodiments of the present invention have been described in detail, it will be appreciated to those skilled in the art that various modifications and alternatives to those details could be developed in light of the overall teachings of the disclosure. Accordingly, the particular arrangements disclosed are meant to be illustrative only and not limiting the scope of the invention which is to be given the full breadth of the following claims and all equivalents thereof. 

1. A relay unit comprising: a plurality of relays; a plurality of fuses; and a power supply bus bar configured to supply current to said plurality of relays; wherein each of said relays includes a pair of switch connecting bus bars between which a relay switch element is intervened and a pair of coil connecting bus bars between which a relay coil element is intervened, wherein one of said switch connecting bus bars is formed with a downstream fuse connector portion to which each of said fuses is electrically coupled and a relay terminal configured to be electrically coupled to a connector, and wherein said downstream fuse connector portion and said relay terminal protrude in directions opposed to one another, wherein the downstream fuse connector portion and the relay terminal are disposed substantially in the same plane.
 2. The relay unit according to claim 1, wherein: the other one of said switch connecting bus bars and said pair of coil connecting bus bars are formed with relay terminals to be electrically connected to relevant connectors, respectively.
 3. The relay unit according to claim 1, wherein: said power supply bus bar is located at an inner surface of a unit case.
 4. The relay unit according to claim 1, wherein: said power supply bus bar is formed with an upstream fuse connector portion; and said downstream fuse connector portion formed on said one of said switch connecting bus bars and said upstream fuse connector portion formed on said power supply bus bar are located in an opposed relationship to form a pair of fuse connector components.
 5. The relay unit according to claim 1, wherein: said plurality of relays are connected to said respective fuses without wires.
 6. The relay unit according to claim 1, wherein: each of said plurality of relays is configured to be physically connected to one of said respective fuses.
 7. The relay unit according to claim 1, further comprising: an electrically conductive trimmer joint portion disposed between some of said pair of switch connecting bus bars and said pair of coil connecting bus bars.
 8. The relay unit according to claim 1, wherein: said pair of switch connecting bus bars and said pair of coil connecting bus bars are configured to be variably connected to each other.
 9. The relay unit according to claim 1, wherein: said relay unit is configured to allow a variety of relay circuit patterns to be formed.
 10. The relay unit according to claim 1, wherein: each of said plurality of relays is configured to allow a variety of relay circuit patterns to be formed.
 11. The relay unit according to claim 1, wherein: said relay terminal is configured to supply power to its respective relay.
 12. The relay unit according to claim 1, wherein: said plurality of relays are configured to be variably connected to each other.
 13. The relay unit according to claim 1, wherein: each of the pair of switch connecting bus bars and the pair of coil connecting bus bars does not include any portion of a printed circuit board. 